1. Field of the Invention
The invention relates to a ring-shaped filter through which material can flow radially. More specifically, the invention relates to a filter element made of a web material that is folded in a zigzag shape, and this filter element is sealingly connected to a ring-shaped end plate.
2. The Prior Art
A material, similar to the material used for the sealing edge of the filter element of the present invention, has been disclosed in EP 0 559 011 A1 and DE 44 41 608 A1 for the manufacture of an end plate of a filter element. A disadvantage of these known references is the entire end plate is comprised of the material, and there is no complete material separation between the embodied areas. In EP 0 599 011 A, the sealing edge area is reinforced by the introduction of additional material to provide a satisfactory sealing action. The same is shown in DE 44 41 608 A1 since the entire end plate is made of the same basic material that is provided in the radially sealing area. In addition, the material can be softened, then hardened, thereby exhibiting elastic properties.
In a filter element according to EP 0 773 052 A1, an elastic sealing material made of a non-woven material is used as a sealing edge in the filter end plate. To function satisfactorily as a seal, it must be chambered by adjacently positioned, relatively rigid end plate material or applied in multiple layers welded to one another. In addition, the manufacturing method disclosed in this reference is complicated, and the sealing edge is not safe.
Moreover, WO 97/41939 discloses end plates of a ring-shaped filter. However, instead of using a formed sealing material, a material is provided which must be connected, either as a sealing ring in the pre-fabricated state to the end plate, or must be provided with the required elasticity by a spring means.
EP 0 559 011 A1 describes ring filter elements in which the end plates are comprised of a non-woven material, at least in those areas where a sealing action is to be provided.
It is an object of the present invention to provide an end face radial sealing edge that is placed tightly on a connecting part. In addition, the present invention provides an economical and safe filter material cover at the end face. Ring filter elements are used in filters for fuel and lubricants in internal combustion engines of vehicles.
These and other objects are accomplished by providing a ring filter element having at least one end plate forming a first area made of a first material. The first area extends peripherally so as not to cover the radial inner and/or outer edge area. A second area forms the edge areas to provide a seal-tight placement onto a connecting part. The second area is made of a second material different from the first material. The invention also relates to the method for manufacturing such a filter element.